Blower wheel wedged end blade mounting



Dec. 21, 1965 A. M. OLMSTED ET AL 3,224,668

BLOWER WHEEL WEDGED END BLADE MOUNTING Filed Jan. 22, 1965 FIB-:2 lFlEziFIE-:3

JINVENTIJRE ALLAN M. DLMSTEID VERNDN H. WiLlJAMS A TTURNEY United StatesPatent C) 3,224,668 BLOWER WHEEL WEDGED END BLADE MQUNTING Allan M.()lmsted and Vernon H. Williams, Columbus,

IntlL, assignors to Vernco Corporation, Columbus, ]ind.,

a corporation of Indiana Filed Jan. 22, 1965, Ser. No. 427,381 8 Claims.(Cl. 230-434) This invention pertains to the securing of blades betweentwo circular members in a blower wheel or the like, and particularlyinvolves the use of longitudinally extending fingers from the blades andinsertion of the fingers through spaced apart holes around the circularmembers and the lateral expansion of the fingers across the holes tohave the marginal edges of the fingers compressively engage oppositesides of the holes, this lateral expansion of the fingers being had bybending the fingers over onto a face of the circular member oppositefrom the face abutted by ends of the blades.

The primary object of the invention herein described and illustratedresides in the provision of means whereby a positive, secure mounting ofblades may be had between two circular members, in a manner avoidingtendency of twisting of the finished wheel by one of the circularmembers rotating a distance greater than the other. This relativerotation is avoided in the present invention. Also, the inventionprovides for a continued firm pressure by the circular members againstthe ends of the blades.

A further important object of the invention resides in the fact that theblades, have fingers, at least one at each end thereof, which fingersmay be freely inserted through holes in the two circular members in afree sliding manner without an initial force fit, and then the fingersbent over onto the outer faces of the two circular members and expandedin the holes.

A still further important object of the invention is found in the factthat an extremely rigid overall structure is had with the use of aminimum amount of material.

These and other objects of the invention will appear in the followingdescription of one particular form as now best known to us and asillustrated in the accompanying drawing, in which:

FIG. 1 is a view in front side elevation of a blade formed in accordancewith the invention;

FIG. 2 is an end view of the left hand end of the blade shown in FIG. 1;

FIG. 3 is an end view of the right hand end of the blade shown in FIG.1;

FIG. 4 is a top plan view on an enlarged scale of a tongue insertedthrough a hole in one of the circular plates;

FIG. 5 is a similar view on a somewhat larger scale and showing thefinger turned over onto the face of the circular member;

FIG. 6 is a View in section on the line d-6 in FIG. 5;

FIG. 7 is a view in section on the line 77 in FIG. 5;

FIG. 8 is a view in end elevation of a fragmentary portion of a blowerwheel partially assembled to include a ring, a back plate, and a numberof blades;

FIG. 9 is a view similar to the structure shown in FIG. 4 but with adifferent shape 'hole through a ring; and

FIG. 10 is a view in side elevation of a completely assembled blowerwheel.

In the present invention, the blades are formed individually and eachblade 11 has a finger 12 extending longitudinally from one end and afinger 13 extending longitudinally from the other end. These blades arecurved transversely, and in the operation placing this curved shape inthe blade, each of the fingers 12 and 13 is deformed from its originalfiat shape, preferably into a wide spread V with the legs thereof, FIG.4, indicated by the numerals 14 and 15 forming an obtuse angletherebetween.

The blower wheel is, in a majority of constructions, formed to have arear circular member 16 commonly referred to as a back plate having acircular contour or peripheral portion, and to have an intake end ring17 in the nature of a fiat annulus. Both the plate 16 and the ring 17have holes punched around circumferential lines of common radius to havethese holes equally spaced apart around those lines.

Each of these holes is punched to have a marginal shape where there is astraight line 18 on the leading side of each of the holes in respect tothe direction of rotation of the wheel, these holes being generallydesignated by the numeral 19, and the ends of the line 18 are joined inone form by ends of an arcuate line 20.

Each of the holes so shaped provides an opening which will freelyreceive the tongue 12 therethrough, with the edges 21 and 22 of thetongue 12 in close proximity with the junctures of the ends of the line18 with the ends of the arcuate line 20. However the tongue 12 willslide freely through the hole 19.

As will be observed, this shape of hole prevents the insertion of thefinger 12 in the reverse manner. This insures that, in assembling, everyblade 11 will be assembled to have its air moving side as viewed in FIG.1 presented in the correct direction.

The overall projected width of the finger 12 across the legs 14!- and 15is made to be, for one particular size of blade and blower wheel, .005to .010 inch less than the distance between the junctures of the linesreferred to. Within that range of dimensions, the obtuse angle betweenthe legs 14 and 15 is made to be such that when the portion of thefinger 12 projecting through the ring 17 is bent over onto the outsideface 17a as indicated in FIGS. 5 and 6, the V-shape of the finger 12will be changed into a more or less flat state which requires that theedges 21 and 22 of the finger presented within the hole 19 will becarried farther apart and the finger will progressively increase inwidth as the finger is bent over into the portion 12a, those edges infact really biting into the metal in the line junctures and bemaintained in that engagement by reason of the finger 12 being bent oversubstantially at right angles to the portion in the hole, the bend line23 maintaining the fiat shape of the two portions of the finger, namelythe portion within the hole 19 and the portion compromising the bentover length. When the fingers 12 and 13 are formed into the V-Shape,there will be a slight deformation 29 in the ends of the blades at thebase or root of the fingers, and this deformation tends to disappear inthe bending of the fingers as above indicated.

A feature of the invention resides in a bead 30 extending longitudinallyof the finger in each instance which automatically forms on the fingeron the side removed from the angle apex line 28 as the finger is bentover as in FIGS. 5-7. This bead 30, in so forming, performs an importantfunction. It extends from the blade end, through the hole 19, and alongthe bent over length 12a to approximately the outer free end portion 12bof the finger. In so extending, the bead 30 reinforces the bend 23 andeffectively maintains the end portion 12b in compressive contact withthe face 170. There is a degree of elasticity in the bent over fingersin respect to their contacts with the ring and plate which is highlydesirable as means for continuously compressively embracing the bladestherebetween, thereby preventing the loosening of the blades between thering and plate after a period of time in service.

In the process of bending the finger into the portion 12a over onto theface 17a, the end of the blade 11,

designated by the numeral 24 extending from the finger 12 on each sidethereof FIG. 7, will be brought into compressive contact with the innerface 17b of the ring 17. Since the blade 11 has a laterally curvedshape, there will be not a straight line engagement between the edge 24,but a curved line as best indicated in FIG.- 8. In other words, there isno tendency for the blade 11 to be tipped from the perpendicular to thering 17 but will be maintained there by reason of the curved zone ofbearing of the edge 24.

Each of the fingers 13 on the ends of the blades 11 opposite to thefinger 12 will be inserted through the holes 19a in the plate 16 inexactly the same manner and they are secured by turning over the tongues13 onto the back side of the plate 16. The holes 19a and 19 are of thesame shape but may vary in dimensions from the holes 19 in the ring 17,with the widths of the fingers varying accordingly.

Referring to FIG. 9, a triangular shaped hole 25 is shown through thering 17 having the straight line 18, and instead of having the arcuateline 20 interconnecting the ends of the line 18, there are the twostraight lines 26 and 27 completing in effect a hole having a marginalshape of an isosceles triangle. The corners between the ends of thelines 26 and 27 adjacent to line 18 are given a radius of approximately.005 to .010 inch as one example, these dimensions being indicated forone particular size of fingers 12, and of the size of the blower wheelfor instance designated as 28, may vary.

Using the triangular hole 25 in each instance, both through the ring 17and through the plate 16, the finger 12 will have a lateral width whenin the V-shape to permit the finger 12 to be inserted through the hole25 rather freely, and by reason of the shape of the hole, the finger 12can only be inserted in the one particular direction. The finger 12 inthe form shown in FIG. 9 is likewise bent over as indicated in FIGS. 7.The edges 21 and 22 of the finger 12 will come into compressiveengagement within the curve between the junctures of the lines 26 and 27with the line 18.

In the use of either the hole 19 or the hole 25, the straight line 18will be on the relatively forward side of the hole, that is on theleading side thereof in respect to rotation of the wheel.

It is to be seen, therefore, that by employing a hole having a straightedge marginal portion, the deformed fingers are always required to beinserted through the holes to properly position the curvature of theblades. In this respect, the lines 18 must be so aligned around the ring17 and the plate 16 to provide for the proper presentation of the blades11 around the wheel. By so doing, the maximum possible effectiveness ofthe wheel may be had for any given curvature of the blades. That is, themaximum flow of air as the case may be is had for that particular bladeshape, and likewise by the presentation of that curvature of the blades,the noise level may be controlled for that particular blade shape.

While the use of a single finger on each end of each blade is entirelysufficient for structural strength in small diameter blower wheels,additional fingers may be employed at each end of the blades where thestructure is increased in size and greater strength is requiredaccordingly.

While the finger portions 12a may be preferably left in the turned overconditions, they may of course be fixed to the ring and plate by anysuitable means, such as by welding, soldering, brazing, and the like, ormay even be maintained by placing a circular band thereover (not shown)as is done in many cases.

Therefore, while we have described our invention in this particularform, changes may be employed without departing from the spirit of theinvention, and we therefore do not desire to be limited to this preciseform beyond the limitations which may be imposed by the following a ms.

We claim: 1. In a blower wheel, an interconnection of a blade end with ablade carrying member, comprising a blade; a finger extending integrallyfrom an end of the blade; a blade carrying member having a holetherethrough; said hole being defined by a straight side wall and a wallreceding from each end of the straight wall forming corners therewith;said finger having been deformed longitudinally; said finger extendingby a length adjacent said blade through said hole to extend beyond by aportion, said length having side edges extending into said corners; saidfinger portion extending at approximately a right angle to its said holelength through a bend over said straight wall into contact with saidmember to one side of said hole; and said bend maintaining said fingerhole length under tension tending to flatten out its deformation andretain said finger edges in compressive lateral engagement with saidwalls in said corners. 2. The structure of claim 1, in which said bladeend is compressively held by said bend against a face of said memberopposite to the face over which said finger portion extends. 3. Thestructure of claim 1, in which said receding wall is transverselyarcuate. 4. The structure of claim 1, in which said receding wall hastwo faces angularly disposed one each toward the other from oppositeends of said straight wall, the two faces intersecting in a line spacedfrom and intermediate the said ends of the straight wall. 5. The methodof forming a connection between a holding member and a fan blade, whichcomprises punching a hole through the member defined by an encompassingwall, one segment of which is fiat and forms corners at each end thereofwith the remainder of the wall; forming a blade to have a straight endand a longitudinally deformed finger extending therefrom with side edgeshaving an overall dimension thereacross less than that of said flat wallsegment; inserting said deformed finger through said hole with thefinger side-edges presented toward said corners and an end portion ofthe finger extending from said hole; holding said blade straight andbending said finger at approximately a right angle over said fiat wallonto said member, thereby stressing said finger and flattening it amajor degree and increasing the tongue width forcing said side edgesinto compressive engagement in said corners with said hole wall, andpulling said blade end compressively against said member. 6. The methodof forming a blower wheel, which comprises forming two circular plateseach with a common number of holes therethrough and on commoncircumferential lines therearound; punching each of said holes to have astraight side thereof merging through acute angles into the remainder ofthe hole encompassing wall; forming a plurality of blades each havingopposite straight ends; forming a finger to extend longitudinally fromeach blade end, the finger being formed into approximately V-shape withdiverging legs terminating in side edges of the finger; said fingerseach having a lateral width across said side edges to permit entry ofthe fingers through said holes; inserting the fingers through said holesand abutting said blade straight ends respectively against said twoplates;

end against said member;

bending portions of said fingers extending from said holes sharply oversaid hole flat sides onto said plates;

said bending flattening said fingers to a major degree driving said legside edges into said angles and compressively engaging those side edgesagainst the hole Wall forming said angles; and

flattening said finger portions against said plates.

7. The method of claim 6 in which said holes are punched to arcuatelyshape said encompassing Wall.

8. The method of claim 6, in which said hole is punched to have saidencompassing Wall be two flat Walls completing an isosceles trianglewith said straight side.

References Cited by the Examiner UNITED STATES PATENTS Ness 295 13 Doman230134 Touche 29-513 Hathaway 29-513 Mayne 29l56.8 Holcombe 29-513 XMARK NEWMAN, Primary Examiner.

1. IN A BLOWER WHEEL, AN INTERCONNECTION OF A BLADE END WITH A BLADECARRYING MEMBER, COMPRISING A BLADE; A FINGER EXTENDING INTEGRALLY FROMAN END OF THE BLADE; A BLADE CARRYING MEMBER HAVING HOLE THERETHROUGH;SAID HOLE BEING DEFINED BY A STRAIGHT SIDE WALL AND A WALL RECEDING FROMEACH END OF THE STRAIGHT WALL FORMING CORNERS THEREWITH; SAID FINGERHAVING BEEN DEFORMED LONGITUDINALLY; SAID FINGER EXTENDING BY A LENGTHADJACENT SAID BLADE THROUGH SAID HOLE TO EXTEND BEYOND BY A PORTION,SAID LENGTH HAVING SIDE EDGES EXTENDING INTO SAID CORNERS; SAID FINGERPORTION EXTENDING AT APPROXIMATELY A RIGHT ANGLE TO ITS SAID HOLE LENGTHTHROUGH A BEND OVER SAID STRAIGHT WALL INTO CONTACT WITH SAID MEMBER TOONE SIDE OF SAID HOLE; AND SAID BEND MAINTAINING SAID FINGER HOLE LENGTHUNDER TENSION DEFINING TO FLATTEN OUT ITS DEFORMATION AND RETAIN SAIDFINGER EDGES IN COMPRESSIVE LATERAL ENGAGEMENT WITH SAID WALLS IN SAIDCORNERS.